Electrical switch.



PATENTED JUNE 20, 1905.

H. PFIRMANN.

ELECTRICAL SWITCH.

APPLICATION FILED AUG.20, 1902.

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M91358: 1% Ma PATENTED JUNE 20, 1905.

H. PFIRMANN. ELECTRICAL SWITGH.

APPLICATION FILED AUG. 20, 1902.

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No. 792,845. PATENTED JUNE 20, 1905. H. RFIRMANN.

ELECTRICAL SWITCH.

APPLICATION FILED AUG. 20, 1902.

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ammo c NITED STATES Patented June 20, 1905.

HUBERT PFIRMANN, OF FRANKFORT-ON-THE-MAIN, GERMANY.

ELECTRICAL SWITCH.

SPECIFICATION forming part of Letters Patent No. 792,845, dated June 20, 1905.

Application filed August 20,1902. erial No. 120,371.

To all whom it may concern:

Be it known that I, HUBERT PFIRMANN, a subject of the German Emperor, and a resident of Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Electrical Switches, of which the following is a specification.

My invention relates to electrical switches such as are used for sending current impulses into an electric circuit. The present invention may be used, for instance, in connection with a safety device for railways invented by me and forming the subject-matter of my Letters Patent of the United States N o. 7 2,487, dated October 27, 1908. In said safety device I employ sources of electricity carried on the rolling-stock (say two trains traveling on the same line) in combination with a track-circuit and current-reversing switches driven by the movement of the rolling-stock for sending periodic current impulses from said sources of electricity into said track-circuit. These impulses operate an alarm or a brake, or both. New each switch has a position in which it interrupts the circuit. In practical use it might happen that, for instance, withone of the trains standing still a switch would stop in its inoperative or open position. In such a case the safety device (alarm or brake) would fail to operate. To provide simple and e'fiicient mechanism for preventing this contingency is the purpose of my present invention. The invention, however, is applicable wherever switches or controllers are employed for sending periodical current impulses into a circuit.

I will now describe in detail the form of my invention shown in the accompanying drawings and will then point out its novel features in the appended claims.

Figure 1 is a plan of the improved mechanism. Fig. 2 is a side elevation with parts in section. Fig. 3 shows the same parts as Fig. 2 in a different position. Fig. 4 is a front elevation of the switch proper, and Fig. 5 is a diagram illustrating the application of my invention to two engines.

The cylinder a is pivoted at (Z to a disk Z), rigidly connected with the circuit reverser or switch 0, mounted to oscillate in suitable bearings and engaged by brushes 0, which are suitably connected with a source of electricity, such as battery A, Fig. 1, and with a suitable circuit, such as a track-circuit, to send current impulses (generally alternating in direction or polarity) into said circuit as the switch oscillates. In the example shown the two brushes at the center of the switch would be connected with the battery-poles and the two end brushes with the circuit receiving the current impulses. Obviously there is a position of the switch 0 in which both central brushes engage the insulation between the switch-sections, and in this event no current will pass through the circuit. To prevent the switch from stopping in this inactive position and to impart an oscillating motion to said switch, I provide the following mechanism: The cylinder at contains a piston, more fully described hereinafter, which is connected by a piston-rod g with a crank-pin on a gear-wheel i, driven in any suitable manner, as by means of a pinion 7' on a shaft Z2, which receives a rotary motion through the medium of a sprocket-wheel Z, which may be driven by the motion of the engine or train, as by means of a chain (not shown) passing around a sprocket (not shown) on the axle of the engine or car. The mechanism so far described would simply impart an oscillating motion to the switch 0. To prevent the switch from stopping in the open or inactive position and to quickly throw the switch from one position to another, the following arrangement has been shown: The pivot d is off the center or axis about which the switch 0 oscillates, and the disk I) is provided with two peripheral notches e f, separated by a lug a. This lug is adapted to be engaged on one side or the other by a hook g on the free end of a locking-lever p, fulcrumed at 9" upon a sup port 8 and pressed toward the disk o by a spring t. The other end of the lever 12 is provided with a toe a, engaging a cam a), rigid with the gear-wheel Q1 and arranged to swing the hook (1 clear of the lug a at certain times, as will be explained presently. The pistonrod g is of reduced diameter within the cylinder a, forming a shoulder against which a piston-ring m is held at times by a coiled a slight pivotal movement on the pin (Z.

spring 0. The other end of the spring is arranged to press another piston-ring n against a head w at the free end of the piston-rod 1.. The rings on w, are adapted to abut against the heads of the cylinder a and are capable of sliding on the reduced portion of the rod g. In the position shown in-Fig. 2 the disk 6,

wvhich has been rocking with the switch 0 in the direction indicated by the arrow, has just reached the point where it is detained by the engagement of the hook g with the lug e. The switch will therefore be held stationary, while the piston continues to move toward the right. This causes the spring 0 to be compressed between the rings ma, the cylinder (1/ having no movement at this time except As the gear-wheel 2' and cam '0 continue to rotate in the direction indicated by the arrow the cam will raise the hook q clear of the lug e, and the spring 0 will quickly throw the released disk 5 and switch 0 into a position substantially as shown in Fig. 3, (so far as the disk 5 is concerned.) When the next depression of the cam 41 is reached, the hook 9 comes to the right of the projection or lug e and arrests the clockwise motion of the disk 5. When during the movement of the piston-rod g to the left the ring 97. engages the outer piston-head, the spring 0 is compressed by the ring on, and as soon as the cam 7.: again swings the hook 11 clear of the lug a the spring will throw the disk I) back to the position shown in Fig. 2. The switch 0 should be so set relatively to the disk 7) that the movement of the disk under the influence of the spring 0 will always carry the switch past its inactive position. The switch, therefore, can never stop in its inactive position, since it is arrested by the hook 9 before it reaches the inactive position and is thrown beyond said inactive position whenever released from the hook q. The piston-rings m a may fit tightly into the cylinder a, so that the latter will serve as a dash-pot.

The device herein described has proved strong and eflicient to prevent a stoppage of the switch in its inactive position both while the mechanism is running and when it is at a standstill.

In Fig. 5 I have shown diagrammatically two engines B B, each carrying a battery A A and a current-reversing switch C C of the character herein before'described in detail. The poles of each battery are connected with the central brushes 0' of Fig. 1. One of the other two brushes is connected with a trackconductor D, the fourth brush being suitably grounded. In any part of the engine-circuit is included a safety device (alarm or brake) E E, which obviously will be operated whenever the engines B B are within a certain distance from each other, provided opposite poles of the batteries A A are at the time connected with the track-conductor D. Such a condition, however, will always occur sooner or later, since the speed of the two engines and the rate of oscillation of the two switches C C will in practice never be exactly the same.

I claim as my invention 1. Incombination with a rocking switch, mechanism for driving the same, a device for temporarily detaining the switch, an elastic device arranged to be put under tension by the driving mechanism while the switch is detained, and means, operatively connected with the driving mechanism, for throwing the detaining device out of action and allowing the said elastic device to throw the switch beyond its inactive position.

2. In combination with a rocking switch, a cylinder pivotall y connected therewith at a distance from the axis of oscillation, a piston arranged in said cylinder, driving means for operating the piston to rock the switch, means for temporarily detaining the switch, means put under tension by the movement of the piston when the switch is detained, and a device for releasing the switch after the last-named means has been put under tension.

3. In combination with a rocking switch, and a disk connected therewith and having a projecting lug, a cylinder pivoted'to said disk eccentrieally, a piston arranged in said cylinder, driving means for operating the piston to rock the switch, a locking-lever arranged to engage said lug and detain the disk, means put under tension by the movement of the piston when the disk is detained, and a releasing device, operated by said driving means, for swinging the locking-lever clear of the disk and allowing the switch to be quickly thrown by the means under tension.

4. In combination with a rocking switch, and rotary mechanism for driving the same, a locking device arranged to temporarily detain the switch, means, operatively connected with the driving mechanism, for releasing the switch from its locking device, and means for quickly throwing the switch when released.

5. In combination with a rocking switch, and mechanism for driving the same, a locking-lever one arm of which is arranged to temporarily detain the switch, a cam operatively connected with the driving mechanism and engaged by the other arm of the locking lever, to swing said lever into a releasing position, and means for quickly throwing the switch when released.

6. In combination with a rocking switch, a cylinder pivotally connected therewith at a distance from the axis of oscillation, a pistonrod in said cylinder, driving mechanism connected with said pistonrod, piston rings mounted to slide on the said rod within the cylinder, a spring engaging said rings and adapted to be put under tension by the movement of one ring relatively to the other, means for temporarily detaining the switch, and means for releasing the switch after the spring has been put under tension.

7 As a means for operating a safety device on railway rolling-stock, a source of electric current carried by said rolling-stock, a movable current-reversing switch connected with said source of current and adapted to alternately connect the poles of said source of current with a track-conductor, a device for driving said switch by the movement of the rolling-stock, means for temporarily detaining the switch in an active position, an elastic device arranged to be put under tension by the driving mechanism while the switch is de-" tained, and means, operatively connected with the driving mechanism, for throwing the detaining device out of action and allowing said elastic device to throw the switch beyond its inactive position.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HUBERT PFIRMANN Witnesses JULIUS Mum, KARL MERZ. 

